Hithertofore, a number of physiologically active substances which microorganisms produce have been known. However, none of them is known to have the physico-chemical properties that are identical to those of the PF 1022 substance according to the invention. It is further known that a number of compounds have anthelmintic activity. However, those substances which are produced by microorganisms and have anthelmintic activity, such as the novel PF 1022 substance of the present invention, are in a very small minority, inclusive of destomycin A, hygromycin B and avermectin.
Also, a substance similar in chemical structure to the substance of the present invention is known as bassianolide (Agric. Biol. Chem., 42(3), 629-635 (1978) . However, this substance has no anthelmintic activity.
Parasitic diseases, which are generally caused by parasitic infestation or infection in host animals, cause serious damage to the health of humans and animals and to agriculture. Therefore, the advent of any new anthelmintic is always waited for.